Posted by **Adria** on Tuesday, December 8, 2009 at 8:57am.

In a distribution of 400 response times with a mean of 7 minutes and a standard deviation of 2 minutes, the maximum number of response times greater than 13 minutes would be about:

A. 40

B. 100

C. 75

D. 90

- Statistics -
**Reiny**, Tuesday, December 8, 2009 at 9:58am
According to

http://davidmlane.com/hyperstat/z_table.html

the probability of a time greater than 13 minutes is .00135

None of your choices result from that probability.

- Statistics -
**PsyDAG**, Tuesday, December 8, 2009 at 10:06am
Z = (x - μ)/SD

Z = (13-7)/2 = 6/2 = 3

Look up this Z in a table in the back of your statistics text covering areas under the normal distribution for the smallest area. Multiply this value by 400.

Unfortunately, that does not fit any of your choices. Do you have any typos?

- Statistics -
**Adria**, Tuesday, December 8, 2009 at 12:51pm
No. No typos. That's how its written on the packet I am doing. Thank You so much for your help though, I guess my teacher might've made a typo...

## Answer this Question

## Related Questions

- Statistics - Fire department response time is the length of time it takes a fire...
- statistics - Times for a surgical procedure are normally distributed. There are ...
- statistics - in new york city the average response time for calls to the first ...
- normal distribution - in new york city the average response time for calls to ...
- statistics - Waiting times at a doctor office are normally distributed with a ...
- statistics - Waiting times at a doctor office are normally distributed with a ...
- business statistics - For one of the tasks in a manufacturing process, the mean ...
- Statistics - As reported in Runner's World magazine, the times of the finishers ...
- Q Research - 2. The average commute time via train from the Chicago O'Hare ...
- stat - The average commute time via train from the Chicago O'Hare Airport to ...

More Related Questions